I look forward to the day we can all celebrate the defeat of cholera in Haiti. Yet, one year after the first cases appeared, many in the international community are rushing to this conclusion too soon. Thanks to the efforts of NGOs and funding from international donors, such as the humanitarian aid department of the European Commission (Echo), case fatality rates have dropped significantly since the early days of Haiti's cholera epidemic.

However, this success is fragile – indeed, since the end of August and the arrival of the rainy season, the number of cases has risen again, particularly in Haiti's Sud department, where International Medical Corps (IMC) is the main cholera response agency. If NGOs are not adequately resourced to provide critical cholera prevention and treatment services, and to support the Haitian government in the areas where it is able to provide services, cases will rise and more people will die.

It is now a year since those first cholera cases emerged, and encouraging statistics have caused some donor agencies to declare the emergency phase over. But this remains an emergency that has only temporarily abated. If funding is cut and services closed, infection rates will rise and the relatively low fatality rates that have been achieved thanks to NGO interventions will quickly increase.

Cholera thrives where water systems are weak and sanitation poor. A history of poverty, natural disaster, neglected public water and sanitation systems, and under-resourced health infrastructure has magnified the impact of cholera in Haiti. It is estimated that 80% of Haitians do not have access to latrines and more than half of the population lacks access to safe drinking water.

The US government's health and safety agency, the Centres for Disease Control and Prevention (CDC), has called these conditions a "perfect storm for a massive epidemic of cholera". As of 14 October, about a year from the start of the epidemic, Haiti's ministry of health reported 473,649 cases of cholera and 6,631 deaths attributed to it across all 10 of the country's departments. Haiti is experiencing one of the worst cholera outbreaks in recent memory, and because this epidemic followed the 2010 earthquake and decades of political instability, it has limited capacity to mount a home-grown response.

We will only be able to declare victory over cholera when Haitians have access to toilets and safe water, the government has the resources and the capacity to manage cholera (and Haiti's other health concerns) on its own and reliance on donor funding and NGO partners is no longer needed. Until then, donors and governments must acknowledge that cholera is still an emergency and respond accordingly. Haiti is like a patient on life support – if donors pull the plug now, the patient will not survive on its own.

In my work in Haiti, leading IMC's operations, I see my colleagues saving lives every day. Our work is simple: we help ensure that people have access to safe water to prevent infection, we invest in basic sanitation infrastructure to help keep water clean, and when people do become ill we provide efficient and effective medical care. Cholera is not complicated, but it is deadly.

Yet funding cuts for cholera services have forced us to close most of our treatment sites around the country. Several other NGOs with critical roles in the cholera response have also been forced to scale down or close their programmes, often meaning that those living in remote areas no longer have access to care. In the Sud department, where IMC is managing more than 80% of reported cholera cases, the only other NGO working alongside us plans to close its treatment services in the coming days. Cuts in funding mean cuts in coverage, and that means people will die from a disease that is simple to prevent and easy to treat.

While international funders deserve recognition for their efforts so far, we must not underestimate the severity of Haiti's cholera epidemic. The international community must accept that cholera will continue to be an emergency for the foreseeable future. Governments and donors must honour the commitments we made to Haiti in the aftermath of the 2010 earthquake and following the start of this epidemic. If we don't, many will fall ill, and many will die of a preventable, easily treatable disease.